EP0124465A1 - Ladungskontrollvorrichtung und deren Verwendung zur Tintentropfengeschwindigkeitskontrolle eines Tintenstrahldruckers. - Google Patents

Ladungskontrollvorrichtung und deren Verwendung zur Tintentropfengeschwindigkeitskontrolle eines Tintenstrahldruckers. Download PDF

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Publication number
EP0124465A1
EP0124465A1 EP84460003A EP84460003A EP0124465A1 EP 0124465 A1 EP0124465 A1 EP 0124465A1 EP 84460003 A EP84460003 A EP 84460003A EP 84460003 A EP84460003 A EP 84460003A EP 0124465 A1 EP0124465 A1 EP 0124465A1
Authority
EP
European Patent Office
Prior art keywords
cylinder
charge
drops
time
ink
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP84460003A
Other languages
English (en)
French (fr)
Other versions
EP0124465B1 (de
Inventor
Luc Regnault
Jean-Paul Maingaud
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Markem Imaje SAS
Original Assignee
Imaje SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from FR8307549A external-priority patent/FR2545041B1/fr
Priority claimed from FR8316439A external-priority patent/FR2553339B3/fr
Application filed by Imaje SA filed Critical Imaje SA
Publication of EP0124465A1 publication Critical patent/EP0124465A1/de
Application granted granted Critical
Publication of EP0124465B1 publication Critical patent/EP0124465B1/de
Expired legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/07—Ink jet characterised by jet control
    • B41J2/125—Sensors, e.g. deflection sensors

Definitions

  • the invention relates to a device for controlling the charge of drops in an ink jet printer, as well as its application to controlling the speed of said drops.
  • the ink-jet writing technique using a continuous jet of calibrated droplets, supplied by a modulation system, requires electrostatically charging these droplets by means of an appropriate electrode.
  • the passage of these variably charged drops between plates brought to a high potential leads to a deflection of the drops proportional to the charge and which, combined with the displacement of a support, makes it possible to obtain matrices of printed characters.
  • the proper functioning of the device requires the introduction of means for controlling the accuracy of the charge of the drops. These must meet a certain number of requirements, the main ones being in particular the small size and the great rusticity. The device must not be able to be out of balance, nor be altered by the chemically aggressive environment. Finally, it must be effective and for this it must not risk being disturbed by the neighboring electric fields.
  • the present invention specifically relates to a device capable of controlling the charge of the drops in an inkjet printer meeting all these criteria. It therefore relates more precisely to a device for controlling the charge of ink drops which are fragmented and electrostatically charged in order to be deflected to constitute a matrix of characters printed on a support; characterized in that it comprises a charge detector constituted by the combination of a hollow, conductive, external cylinder, connected to ground M to form a shield; an insulating cylinder inserted into the outer hollow cylinder and in intimate contact with it in which at least one solid cylinder 3 is embedded, this inner cylinder 3, electrically isolated from the shield being connected to a coaxial wire intended to be itself connected to an electronic circuit, a slit of width (e) and length (L) being made and positioned in this detector so that it is on the trajectory of the charged drops which cross it without touching its walls; the charge of each of these drops passing in front of the inner, conductive cylinder, inducing a signal exploited by the electronic circuit.
  • the invention also relates to the application of this charge control device for controlling the speed of drops of an ink jet.
  • this charge control device for controlling the speed of drops of an ink jet.
  • a certain number of operating parameters must be preserved despite the inevitable variations in the environment. This is the case in particular of the speed of the drops: this must be kept constant despite the modifications of the characteristics of the ink such as the viscosity which can change over time. Indeed, under the influence of variations in ambient temperature, or following operating conditions generating an increase in heating, evaporation of the solvent occurs in the more or less long term. This results in a concomitant change in viscosity and therefore speed.
  • the present invention therefore also aims to overcome these drawbacks and relates to a method for controlling the speed of the ink drops; characterized in that it consists in slaving the means for pressurizing the ink to the time (T) that each drop takes to travel a distance (D); this distance being obtained thanks to the use of a charge control device, in accordance with the invention.
  • the inner cylinder 3 is connected by a coaxial wire 11 to an electronic load measurement circuit 12.
  • This coaxial wire 11 is connected to this cylinder 3 by any known means, for example by means of a screw 15.
  • a ground wire 16 connects the external cylinder 1 to the ground M, then making the latter play a shielding role.
  • FIGS. 2a and 2b schematically represent an alternative embodiment of a device according to the invention.
  • this outer cylinder 1, constituting the shielding of the device is filled over a certain length with an insulating material 2 1 , of the same kind as that which was described in the previous embodiment, namely a fluoropolymer as 'a PTFE.
  • an insulating material 2 1 of the same kind as that which was described in the previous embodiment, namely a fluoropolymer as 'a PTFE.
  • two holes are drilled in the insulating sleeve 2 1 , holes into which are introduced two solid cylinders 3 1 and 3 2 which are embedded in the insulating sleeve 2.
  • a slot 10 is made as in the previous case over a length (L) and a thickness (e).
  • the cylinders 3 1 and 3 2 are both connected to an electronic control circuit (not shown in Figures 2a and 2b).
  • FIG. 3 A nonlimiting exemplary embodiment of an electronic circuit 12 intended to cooperate with a detector 100 according to the invention is shown diagrammatically in FIG. 3.
  • the detector 100 consisting of its outer shield 1, grounded m and its slot 10 is connected by a coaxial tube 11 to the input E of the circuit 12.
  • the latter has four essential parts, the first A which is constituted by the combination of a Resistor RI and two diodes dl and d2 of reverse polarity has the function of protecting the device against accidental overvoltages originating from the presence of high voltages on the detector 100.
  • the second B is a bandpass filter constituted by a high gain amplifier (Al - R5 - C2).
  • the positive input of the latter is connected to a resistor RI itself connected to ground while its negative input is also connected to ground m through the resistor R4 and the parallel Resistor - Capacitor circuit (R3 - CI).
  • the signal at the output of amplifier Al is applied to a hysteresis comparator D through a cell C constituted by a capacitor C3 and a resistor R6 whose function is to block the passage of direct voltages; this hysteresis comparator constituted by an amplifier A2, two resistors R7 and R8 and a potentiometer Pl provides at the output S of the electronic circuit 12, a logic signal usable by control means of known type, capable of measuring the amplitude of the signal present at exit S.
  • such a charge control electrode can also perform a second function: namely that of a device for controlling the speed of the ink drops as explained below.
  • the pressurization of the ink in the printer is ensured by means of a gear pump of a type known per se controlled by a stepping motor. It is precisely the qualities of these pressurizing means that are used in the present invention to, according to an important characteristic, reduce the speed of each drop to a constant value by varying the pressure as a function of precisely the evolution of this speed.
  • the method according to the invention therefore consists in continuously measuring the speed of the drops and in controlling this data, the operation of the pressurizing pump.
  • the measurement of the speed consists in determining the time (T) which elapses between the time the first drop leaves the spray; this phenomenon occurs in the so-called “breaking zone” and the moment when this drop passes through an electrode whose primary function is to control the charge of each drop and which is called for this "charge control electrode".
  • T time
  • the breaking zone is known, therefore the distance (D) comprised between the latter and the charge control electrode. From the distance (D) traveled and the time (T) taken by the drop to travel it therefore deduces its speed (V).
  • the stepping motor When the printer is put into service, all of the charge and charge control electrodes being switched off, the stepping motor is given a set point according to a predetermined program corresponding to a speed of rotation considered as maximum.
  • the pressure delivered is then much higher than normal pressure, of the order of one and a half times.
  • the charge and charge control electrodes are switched on, which in accordance with the invention, in addition to their primary function, will play here a second function, namely that of detecting the instant of passage of the drops at their level.
  • the jet break Given the high pressure, the jet break is very far from the nozzle and is located outside the charging electrode or, in any case, not in the middle of it as is the case. case in normal operation.
  • a few drops are then loaded lightly so as to measure the effect of the application of this charging voltage. This is low enough that the charged drops are not, however, sufficiently deflected to exit the recovery gutter.
  • the evolution of the load measurement signals on the charge control electrode is then followed, while the machine program commands the latter to gradually
  • the break is detected. It is located at one end of the charging electrode. The modification of the pressure then ceases to take place in a programmed manner.
  • the motor takes a few steps (of the order of 3 to 4) sufficient and just sufficient for an additional pressure decrease to take place, such that the breaking zone is brought back to the center of the charging electrode.
  • the pressure applied at the time when this result is obtained, leads to a determined jet speed for example very close to 20 meters per second corresponding to time (T). The machine is then ready for operation.
  • the parameter Time (T) being thus measured in one and the other variant of implementation of the method according to the invention, the supply frequency of the stepping motors which control the pressurization pumps is varied. in order to keep this time (T) constant.
  • the process in accordance with the invention applies to all ink jet print heads comprising a charge electrode and at least one charge control electrode and means capable of varying the pressure of the ink, this pressure variation being controlled by signals taken from the electronic circuits controlling the charge of the droplets and the control of this charge.
  • a charge control device proves to be very effective for measuring drop charges not exceeding a few picocoulombs. It is intended to equip the printheads for inkjet printers, whether the single variant or the double variant.
  • the production of the slot 10 is preferably carried out when the detector is already positioned in the print head. Thus its centering can be optimized which increases the reliability of the device.
  • the invention applies to all inkjet printers.

Landscapes

  • Particle Formation And Scattering Control In Inkjet Printers (AREA)
EP84460003A 1983-04-29 1984-04-25 Ladungskontrollvorrichtung und deren Verwendung zur Tintentropfengeschwindigkeitskontrolle eines Tintenstrahldruckers. Expired EP0124465B1 (de)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
FR8307549 1983-04-29
FR8307549A FR2545041B1 (fr) 1983-04-29 1983-04-29 Dispositif de controle de charge des gouttes et tete d'imprimante a projection d'encre qui en est equipee
FR8316439A FR2553339B3 (fr) 1983-10-13 1983-10-13 Procede de controle de la vitesse des gouttes d'encre d'une imprimante a jet d'encre, et tete d'impression permettant la mise en oeuvre du procede
FR8316439 1983-10-13

Publications (2)

Publication Number Publication Date
EP0124465A1 true EP0124465A1 (de) 1984-11-07
EP0124465B1 EP0124465B1 (de) 1988-10-26

Family

ID=26223421

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84460003A Expired EP0124465B1 (de) 1983-04-29 1984-04-25 Ladungskontrollvorrichtung und deren Verwendung zur Tintentropfengeschwindigkeitskontrolle eines Tintenstrahldruckers.

Country Status (3)

Country Link
US (1) US4590483A (de)
EP (1) EP0124465B1 (de)
DE (1) DE3474792D1 (de)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4688047A (en) * 1986-08-21 1987-08-18 Eastman Kodak Company Method and apparatus for sensing satellite ink drop charge and adjusting ink pressure
US5517216A (en) * 1992-07-28 1996-05-14 Videojet Systems International, Inc. Ink jet printer employing time of flight control system for ink jet printers
US5969733A (en) * 1996-10-21 1999-10-19 Jemtex Ink Jet Printing Ltd. Apparatus and method for multi-jet generation of high viscosity fluid and channel construction particularly useful therein
US6003980A (en) 1997-03-28 1999-12-21 Jemtex Ink Jet Printing Ltd. Continuous ink jet printing apparatus and method including self-testing for printing errors
US6767088B2 (en) * 2001-07-16 2004-07-27 Hewlett-Packard Development Company, L.P. Methods and systems for detecting and determining trajectories of ink droplets

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2210143A5 (de) * 1972-12-11 1974-07-05 Ibm
US3852768A (en) * 1973-08-17 1974-12-03 Ibm Charge detection for ink jet printers
US3953860A (en) * 1973-03-12 1976-04-27 Nippon Telegraph And Telephone Public Corporation Charge amplitude detection for ink jet system printer
US3977010A (en) * 1975-12-22 1976-08-24 International Business Machines Corporation Dual sensor for multi-nozzle ink jet
US4007463A (en) * 1973-03-12 1977-02-08 Nippon Telegraph And Telephone Public Corporation State detection arrangement for ink jet system printer
US4045770A (en) * 1976-11-11 1977-08-30 International Business Machines Corporation Method and apparatus for adjusting the velocity of ink drops in an ink jet printer
US4063252A (en) * 1976-11-11 1977-12-13 International Business Machines Corporation Method and apparatus for controlling the velocity of ink drops in an ink jet printer
FR2471278A1 (fr) * 1979-12-07 1981-06-19 Hertz Carl Procedes et appareils pour produire une file de gouttelettes et pour l'impression par jet d'encre

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS56154069A (en) * 1980-04-30 1981-11-28 Sharp Corp Detecting device for amount of electrification of ink particle in ink-jet printer
US4417256A (en) * 1980-05-09 1983-11-22 International Business Machines Corporation Break-off uniformity maintenance
US4470052A (en) * 1981-04-10 1984-09-04 Recognition Equipment Incorporated A-C Coupled, modulator based, phase-error sensing for IJP
US4460905A (en) * 1982-03-29 1984-07-17 Ncr Corporation Control valve for ink jet nozzles

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2210143A5 (de) * 1972-12-11 1974-07-05 Ibm
US3953860A (en) * 1973-03-12 1976-04-27 Nippon Telegraph And Telephone Public Corporation Charge amplitude detection for ink jet system printer
US4007463A (en) * 1973-03-12 1977-02-08 Nippon Telegraph And Telephone Public Corporation State detection arrangement for ink jet system printer
US3852768A (en) * 1973-08-17 1974-12-03 Ibm Charge detection for ink jet printers
US3977010A (en) * 1975-12-22 1976-08-24 International Business Machines Corporation Dual sensor for multi-nozzle ink jet
US4045770A (en) * 1976-11-11 1977-08-30 International Business Machines Corporation Method and apparatus for adjusting the velocity of ink drops in an ink jet printer
US4063252A (en) * 1976-11-11 1977-12-13 International Business Machines Corporation Method and apparatus for controlling the velocity of ink drops in an ink jet printer
FR2471278A1 (fr) * 1979-12-07 1981-06-19 Hertz Carl Procedes et appareils pour produire une file de gouttelettes et pour l'impression par jet d'encre

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
IBM TECHNICAL DISCLOSURE BULLETIN, vol. 19, no. 4, septembre 1976, pages 1203-1204, New York, US; R.W. ARNOLD: "Raster scan control for an ink jet printer" *
PATENTS ABSTRACTS OF JAPAN, vol. 7, no. 55 (M-198)[1200], 5 mars 1983; & JP- A - 57 201 668 (FUJI XEROX K.K.) 10-12-1982 *
XEROX DISCLOSURE JOURNAL, vol. 3, no. 3, mai/juin 1978, pages 175-180, Stanford, US; L.W. SCHAEFFER et al.: "Electrostatic voltmeter" *

Also Published As

Publication number Publication date
DE3474792D1 (en) 1988-12-01
US4590483A (en) 1986-05-20
EP0124465B1 (de) 1988-10-26

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